60 F is about right. Much colder, and the worm activity will slow down to... Dare I say it?... a crawl.

If you get too far below 60 F, you could start killing off your worms. At 60 F, the will survive, but you will notice the bin slowing down.

The ambient air temperature doesn't matter as much as the temperature inside the bin. If you add enough food so it 'heats' up the bin a little, you can turn your thermostat down some.

Here's a nice little experiment to try. Start off at 60F and check the bin temp. Start adding 'hot' worm food [i like alfalfa meal/pellets] and see if you can get the bin temp up to around 80 (in the middle). Once you know how much food you need to add for a specific temperature, add a little more and start lowering the thermostat. Eventually, you will reach an equilibrium. I'm sure I can keep worms in a 40F room (and maybe even colder) and keep the bin temp up to optimal with this method.

Oh, this depends A LOT on the size of the bin. You need to have a large enough bin to create a nice temperature gradient. My flow-thru bin is around 50 gallons. I wouldn't try it with anything less than about a 22 gallon bin.

Something else just occurred to me. It may be much cheaper and more convenient to wrap the bin with heat tape and plug it in. A friendly neighboor Home Depot would be a good place to look.

I don't think I would heat a whole garage for worms only. The heat tape JerilynnC mentions sounds good. I have read of others using heat mats (for starting seedlings), rope lights, and even a string of old holiday lights wrapped around the outside of the bin. WORMS will slow down their activity as it gets colder, but should survive unless the bed freezes.

A garage heated with the "minimum thermostat setting will be based primarily on the needs of my worms." I can't even get my spouse to heat the house to my minimum thermostat needs. Must only need me to survive, not participate in activities.

I do not see the need to heat the garage for Red Wigglers. I suggest keeping the bin off of the floor on a pallet or legs. Insulation on sides and top but maintain air flow.

A tiny 4" by 6" reptile pad might be good. One I saw appeared waterproof including the cord connection.

What JerilynnC said sounds real good.

Here's another wacky idea. :)

I wonder if an aquarium heater in the middle of the bin would work?

Thanks to everyone for their opinions and ideas. They were very helpful to me.

equinoxequinox writes:

A garage heated with the "minimum thermostat setting will be based primarily on the needs of my worms." I can't even get my spouse to heat the house to my minimum thermostat needs.

LOL! You crack me up.

All the comments got me thinking more in terms of a bin-specific solution. I built a stand for my (as of yet unpopulated) Worm Inn. I am thinking that I could staple some plastic sheeting to the sides of the stand and simply insert an incandescent light bulb to provide additional heat. The waterproof reptile pad might be just perfect for the drip pan of the OSCR Jr. The rising warm air might actually increase the aeration.

HB

JerilynnC wrote
"Here's another wacky idea. :)
I wonder if an aquarium heater in the middle of the bin would work?"

I have heard of these used by placing them in a gallon jug of water and putting that in the bin. It distributes the heat to avoid hot spots and provides more even heating.

I keep my bin in my basement here in the almost-upper midwest. Last year in the early spring I had a thermometer on top of my bin and ambient temp was around 55 F. The bins are next to the south exterior wall and below grade.

Rather than heat tape or an incandescent light under the worm inn what if you wrap the worm inn with a string of Christmas lights? I have seen photos of people doing this to keep potted plants warm in the rare freezes in the far south.

sbryce: "60 F is about right. Much colder, and the worm activity will slow down to... Dare I say it?... a crawl. If you get too far below 60 F, you could start killing off your worms. At 60 F, the will survive, but you will notice the bin slowing down."

This may be why my worms are celibate.

Their cellar is 58 right now and I think it gets colder in January, February. I added 4 loaves of bread. We all know where that will lead. The outside of the bin felt less crisply cold than the top were no vermicompost fills it. Maybe 65.

What temperature am I shooting for here?

I live outside of Boise. I have a worm factory in my unheated garage. When I last looked yesterday, they were squirming and thriving in all 4 trays. Must be the shredded leaves in the bedding and all the pumpkin in the trays. This is the 2nd year for them in the insulated but unheated garage. The rest of the the herd are outside, buried in the compost of my raised beds. I filled them in October. Turned some over yesterday and they were still active underneath.

My 12 yr old dog sleeps on a big dog pillow in the garage. I keep her spot heated with an inexpensive clamp-on work light that uses a red heat bulb, the same one used for keeping baby chicks warm.

Mr yan and equinox, what was the temperature *inside* the bin. I use a compost thermometer to check mine.

You want to keep the temp inside the bin between 60 and 90 F, preferably in the low 70s. Worms pretty much like the same temps we do.

I definitely would not waste the money heating the whole garage. I have successfully used Rope light together with an adjustable dimmer switch to keep my two bins toasty warm in an outside location, through three consecutive Winters, with the outside temperatures being below freezing and the inside temperatures being 75-80 F.

Shaul

Now I have ideas of using a fish tank heater in a water ballast, small pump, and something like a brewer's wort chiller (coil of copper pipe used to chill wort from a boil down to where the yeast can survive) to run warm water through the center of a worm bin. While really cool to think about it is far more expense that I am willing to put in.

Anyway I have no clue what the internal temp of my bins would be. Nor do I have a thermometer I am willing to use.

I think I can experiment with adding grains in smallish quantities to help heat up the actively composting region. Things like bread failures and left over rice. Any thoughts on how fine to break up the hard dry bread when mixing with food?

I have never measured the temp. in my bins. Yesterday I ordered a compost thermometer ($10) and a moisture meter ($25). I have a LOT of mass in one of my wormbeds, but it got very wet a few weeks back when the tarp blew off during a storm series (about 7" of rain!). It seems pretty cool right now.

Here ya go, Mr. Yan. 12 bucks on Amazon. Works great.

Here is a link that might be useful: Digital Thermometer

mr_yan: I have used a fish tank heater in a plastic jar with lid. I secured the lid in such a way that evaporation out of the jar is minimal, or I will have to keep filling it up.
I used it in a RM that is outside on the porch. It kept the worms happy. The VC around the jar will become dry, so you will have to keep an eye on it/keep checking that area say once every 2 days?
I used a cheap heater where there is no temp. noted on the dial, onlu up or down. So before I put that in the bin, I tested in the kitchen with an aquarium thermometer. Once I got the setting for 70F, I marked it on the dial so I don't have to keep guessing. I paid about $10 for that aquarium heater. The one I had that is more sophisticated (w. temp. numbers on the dial) is too long and I will need a higher jar which will be to high for my RM. This has worked real well for me before I got the reptile heat cable.
For thermometer, you don't really need to buy an expensive compost thermomter. I use a meat thermometer (true, the shaft is short but it still does the job) and paid about $5 for it. I have about 5 kicking around because I kept forgetting where I buried it last and had to buy a new one.

Im very new at this and i was wondering i have one of those heating mats for starting seeds would that would work if i put it under my 10 gallon tote of red wigglers?
also how do you use those fishs tank heaters i can use all the help i can get thanj you.

tulips101 - a heat pad can work but any heater has risks inherent in its use. Assuming you know about the fire risks there is the added risk of cooking the bin.

A former user here morgan_3 has a good thread to read titled Three Big Mistakes. This thread was started Dec. 23, 2011. One of the mistakes he talks about is leaving a heating pad on too long resulting in a dry brick of compost, worm carcasses, peat moss, and kitchen scraps.

It will be a while before I anticipate thinking about using some type of heater on my bins.

morgan_3 has good points.
I have used a germination heat pad a couple of years ago in a 96 gal garbage bin converted into an FT. It kept the worms alive and active throught the winter; however, similar to the jar I described above, The area directly around it became bone dry. I was concerned about moisture leaking into the wiring and cause an electr. shortage so I wrapped it in heavy duty plastic and sealed with heavy duty electr. tape. I also connected a thermostat to avoid overheating, just like the set up with the aquarium heater in the water jug.
Spring came and I wanted to remove the heating pad and it was way down in the bin. From added food and bedding and I assume also from worm activity. There was a cavity underneath the pad and the VC was bone dry but still crumbly, so was the VC above the pad. I knew the pad will cause VC to dry so I have piled pumkins almost continuously in the centre to avoid over drying but it didn't help. I guess once VC is dry, liquid just rolled off it.
I feel very confident using heating devices in a worm bin PROVIDED it is controlled/connected to a thermostat. Just make sure you don't put the probe right next to the heat element.

As I stated above, I've had good results using rope light for heating. My rope light (with tiny light bulbs, not LED's)is rated at 16w/meter. I have 5-meters=80w. Wrap your hand around a lit 80w bulb and you'll see just how much heat it gives off. Here's what I did. I found a wooden pallet the size of my two bins and placed it on the solid-wooden table that my bins sit on. I then snaked the rope light underneath the pallet with the bins sitting on top. Then I sealed the open areas around the pallet with styrofoam. The only place for the heat to go is up between the slats of the pallet. So I'm not directly heating the bins but rather the air space under them. I then connected a dimmer switch to the rope light so that I have full range between 0 and 80w. Using simple oven thermometers in the bins (long stems with the dial on top), I can adjust the temperature of the bins. I used this system successfully through three consecutive winters with sub-freezing outside temperatures.

Shaul

Nice Shaul, thanks for sharing!

I was just reading the posts on here and i like all the ideas you have i was wondering if there is a type of light bulb or something like one that could heat my bins they are under light bulbs now and with the lids on maybe the direct heat may not hurt them i have air holes on the top and sides of the totes i have heard about heat lights but didnt know anything about them maybe someone could help me i have only had my worms 5 weeks thank you.

Hi i am useing a aqureum heater now it has been in my 10 gallon tote of red wigglers.And around the pint jar i have it in it is staying about 78 and on the outside its 70 degrees it is helping we will see thank you forthe ideas i still think there should be a light bulb that we could use over my totes they have them for reptiles but i bet they would need to be closer that my light socket isit will just have to be something i work on.I guess that is what we do when we are retired this worm farming is great.

Tulips101 keep a close eye on your bin temps or you could cook 'em pretty quick in a small bin. Maybe put the heater on a timer.

I just got my new compost thermometer (18"probe) and my outdoor wormbeds are 60F. They have slowed a little, but still active. Low outside air temps have been near freezing for a week or so, and highs around 48.

""Hi i am useing a aqureum heater now it has been in my 10 gallon tote of red wigglers.""

Be very careful with that small of a bin, Tulips101, a little mishap here or there can kill off most of the worms.
When I teach, I tell students to use at least an 18gal bin to start out with, much more forgiving.

Here is a link that might be useful: 18 Gallon bins

This post was edited by JerilynnC on Sat, Dec 22, 12 at 11:25

The idea seems expensive to me to heat a whole garage for worms. Might want to consider deepening the bedding, insulating the bin, a soil heater cable or others already mentioned. Of course if you really do want to keep the garage heated then the minimum setting will work for them. I have seen 38F bedding temps in two bins last year with no deaths and those were Ef's. They are a tough worm.

I never found the book but I now remember reading the webpage for the woman who wrote Worms Eat My Garbage which is one of the early info sources for US vermicomposting. If I remember correctly she kept an outdoor bin which was built up to be a garden bench. She lived in Kalamazoo MI and this was an outdoor bin which she heated with a light bulb in the bin. I read this somewhere on the wormwoman.com website but I can't find the actual page right now.

Be careful with standard aquarium heaters. At least back when I had a fishtank 10 years ago there were several warnings against running these when not immersed in water. Apparently the glass can and will crack when heating dry.

I have a great thermostat from when I kept an iguana which I now use for starting seedlings. There is a dial to set the temp with three switched outlets on the end of an extension cord. The temp is then measured at a probe with about a meter long cord to the main unit. The main unit is a little smaller than a typical desktop hard drive. While not exact this is a similar unit

Hi All; I use a soil cable with auto temp control. I fasten it it to a piece of plywood.

Here is a link that might be useful: Soil Cable

Well, I ended up using a reptile heating cord in conjunction with a digital thermostat. It works beautifully. I The temperature stays within about a 2-3 degree range that I specify. This is with an uninsulated rubbermaid bin in an unheated garage. The heat cord is only 25 watt.

I have a Worm Inn that I want to kick off soon with EFs. I constructed a wooden frame to hang the Inn from. I will utilize a similar setup to control it. Since I will be heating a larger space, my plan is to attach insulation board to the wooden frame and use a slightly higher wattage heat cord.

HB

hellbender: I am glad it works out for you. I have the same set up with a plastic FT, wooden FT and a RM. I do not have a Worm inn but I often read that it tends to dry out. So does the heater. You'll have to be double as vigilant re. moisture in your Worm Inn.

The reason why the Worm Inn dries out is because it's made of fabric and so it's got air flow on all sides. On the plus side, go to Redworm Composting and read how Bentley fed 20 lb. loads of veggies to his Worm Inn and they went right through it because of the major air flow.

Shaul

I bet if the sides of the hanger platform for the inn are blocked with insulating foam the drying will be slowed greatly. I have been thinking of ways to slow the drying of my worm inn and this type of barrier is one of the ideas. I have found that it is really just the outer edge of the inn near the fabric that drys. It was the outer 4 or 5 cm of the worm casting / bedding media that was dry when I when digging yesterday.

otis11 writes:

"You'll have to be double as vigilant re. moisture in your Worm Inn."

Agree.

shaul writes:

"The reason why the Worm Inn dries out is because it's made of fabric and so it's got air flow on all sides. On the plus side, go to Redworm Composting and read how Bentley fed 20 lb. loads of veggies to his Worm Inn and they went right through it because of the major air flow. "

Yes, that was pretty amazing. I believe I read somewhere that the situation with the outer edges drying out could be addressed by adding water periodically along the top edges of the reactor. Also, that most of the compost production is expected to occur in the central "sweet spot" where moisture conditions are more ideal.

mr_yan writes:

"I bet if the sides of the hanger platform for the inn are blocked with insulating foam the drying will be slowed greatly. I have been thinking of ways to slow the drying of my worm inn and this type of barrier is one of the ideas."

Yes. I suppose it is also possible that this effect would be negated somewhat from increased airflow caused by convection from the heating cable. I am treating this as an experiment and will report photos and results here.

HB